SPRUII0F May 2019 – June 2024 TMS320F28384D , TMS320F28384D-Q1 , TMS320F28384S , TMS320F28384S-Q1 , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S
31 | 30 | 29:28 | 27 | 26 | 25:24 | 23 | 22:18 | 17 | 16 | 15:0 |
---|---|---|---|---|---|---|---|---|---|---|
OWN | CTXT | Rsvd | OSTC | TCMSSV | Rsvd | CDE | Rsvd | IVLTV | VLTV | VT |
Bit | Name | Description |
---|---|---|
31 | OWN | Own Bit |
When this bit is set, the bit indicates that the Ethernet module DMA owns the descriptor. When this bit is reset, the bit indicates that the application owns the descriptor. The DMA clears this bit immediately after the read. | ||
30 | CTXT | Context Type |
This bit can be set to 1 for Context descriptor. | ||
29-28 | Rsvd | Reserved |
27 | OSTC | One-Step Timestamp Correction Enable |
When this bit is set, the DMA performs a one-step timestamp correction with reference to the timestamp values provided in TDES0 and TDES1. | ||
26 | TCMSSV | One-Step Timestamp Correction Input or MSS Valid |
When this bit and the OSTC bit are set, the bit indicates that the Timestamp Correction input provided in TDES0 and TDES1 is valid. | ||
When the OSTC bit is reset and this bit and the TSE bit of TDES3 are set in subsequent normal descriptor, the bit indicates that the MSS input in TDES2 is valid. | ||
25-24 | Rsvd | Reserved |
23 | DE | Descriptor Error |
When this bit is set, the bit indicates that the descriptor content is incorrect. The DMA sets this bit during write-back while closing the context descriptor. | ||
Descriptor Errors can be: | ||
Incorrect sequence from the context descriptor. For example, a location before the first descriptor for a packet. | ||
All 1s. | ||
CD, LD, and FD bits set to 1. | ||
Note 1: When Descriptor Error occurs due to All 1s or CTXT, LD, and FD bits set to 1, the Transmit DMA closes the transmit descriptor with DE and LD bits set to 1. When IOC bit in TDES2 of corresponding first descriptor is set to 1, Transmit DMA sets the TI bit in the DMA_CH#_Status register | ||
Note 2: Based on CTXT, LD, and FD bits of the transmit descriptor, the subsequent descriptor can be considered as the First Descriptor (even if FD bit is not set) and partial packet is sent. | ||
22-20 | Rsvd | Reserved |
19-18 | IVTIR | Inner VLAN Tag Insert or Replace |
When this bit is set, these bits request the MAC to perform Inner VLAN tagging or un-tagging before transmitting the packets. If the packet is modified for VLAN tags, the MAC automatically recalculates and replaces the CRC bytes. | ||
The following list describes the values of these bits: | ||
00: Do not add the inner VLAN tag. | ||
01: Remove the inner VLAN tag from the packets before transmission. This option can be used only with the VLAN frames. | ||
10: Insert an inner VLAN tag with the tag value programmed in the MAC_Inner_VLAN_Incl register or context descriptor. | ||
11: Replace the inner VLAN tag in packets with the tag value programmed in the MAC_In ner_VLAN_Incl register or context descriptor. This option can be used only with the VLAN frames. | ||
These bits are valid when the Enable SA and VLAN Insertion on Tx and Enable Double VLAN Processing options are selected. | ||
17 | IVLTV | Inner VLAN Tag Valid |
When this bit is set, the bit indicates that the IVT field of TDES2 is valid. | ||
16 | VLTV | VLAN Tag Valid |
When this bit is set, the bit indicates that the VT field of TDES3 is valid. | ||
15-0 | VT | VLAN Tag |
This field contains the VLAN Tag to be inserted or replaced in the packet. This field is used as VLAN Tag only when the VLTI bit of the MAC_VLAN_Incl register is reset. |